The technique developed during the past grant period for amino acid sequencing of peptides in the complex mixtures encountered in the determination of the primary structure of proteins is being utilized for the confirmation of the proposed structure of neocarzinostatin, a protein of 109 amino acids exhibiting antitumor and antibiotic activity, and of collagenase A. Because of the latter's action of the ubiquitous structural protein, collagen, its primary structure is of great interest. In the course of this work the experimental technique will be improved to achieve a further increase in speed, sensitivity and efficiency, particularly through refinement (perhaps even automation) of the chemical steps, the gas chromatographic separation (directly and through data processing techniques), and computer-aided interpretation of the data.